Multicontact vacuum-type high-voltage circuit breaker utilizing a liquid metal and drawing a plurality of series arc

ABSTRACT

A high-voltage vacuum-type circuit breaker is provided having multiple spaced contacts, or electrodes, which are sequentially removed, or withdrawn from a pool of a liquid metal, such as gallium, or its alloys. A multiplicity of series arcs are thereby established, which are moved from the end electrodes to the adjacent surfaces of the intervening spaced electrodes. This enables a high-voltage circuit to be interrupted by the establishment of a number of arcs in series. If desirable, magnetic means may be employed to effect lateral movement of the established arcs. Gallium is particularly favorable for my circuit breaker application because of its extremely low vapor pressure in vacuum. In another circuit breaker arrangement, an insulating rotating disc, or wheel carries a number of spokelike contacts, or electrodes, which are sequentially withdrawn from the pool of liquid metal to establish a plurality of series arcs.

I United States Patent [72] Inventor Russell E. Fox 3,052,783 9/1962Buron 200/145 Pittsburgh, Pa. 3,462,573 8/1969 Rabinowitz et al. 200/144(B) [21] pp M 89.5 FOREIGN PATENTS [221 PM 288,195 10/1915 Germany200/144 (AP) [45] Patented July 13, 1971 [73] Assignee WestinghouseEleflric Corporation 341,486 10/1921 Germany 200/144 (AP) pmsburgmpa.25,451 12/1899 Great Britain 200/144 (AP) Primary Examiner-Robert S.Macon Amr v --A. T. Stratton. Cl m m L. M H l d s4 MULTICONTACTVACUUM-TYPE morrt g 6 e c a e w'nard VOLTAGE CIRCUIT BREAKER UTILIZING AM LI UID METAL AND W I Y F sEgms ARC DRA ING A PLURAL T 0 ABSTRACT: Ahigh-voltage vacuum-type circuit breaker is 11 Claim D provided havingmultiple spaced contacts, or electrodes, "wing [gs which aresequentially removed, or withdrawn from a pool of U.S. a metal uch asgallium or its alloys. A multiplicity of ZOO/145, 200/ 152 series arcsare thereby established, which are moved from the Int. end electrgdes tothe adjacent surfaces of the intervening H01 h 29/00 spaced electrodes.This enables a high-voltage circuit to be inof terru ted theestablishment ofa number of arcs in eries 15210, 152 desirable, magneticmeans may be employed to effect lateral movement of the establishedarcs. Gallium is particularly [56] References cued favorable for mycircuit breaker application because of its ex- UNITED STATES PATENTStremely low vapor pressure in vacuum. 437,412 9/1890 Deprez 200/153(.10) In another circuit breaker arrangement, an insulating rotat-468,Il9 2/1892 Thomson 200/144 (AP) ing disc, or wheel carries a numberof spokelike contacts, or 532,838 895 h m n 200/ I44 (AP) electrodes,which are sequentially withdrawn from the pool of 535,077 3/1895 Potter200/ 144 (AP) liquid metal to establish a plurality of series arcs.

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FULLY- OPEN POSITION MULTICONTACT VACUUM-TYPE HIGH-VOLTAGE CIRCUITBREAKER UTILIZING A LIQUID METAL AND DRAWING A PLURALITY OF SERIES ARCCROSS-REFERENCES TO RELATED APPLICATIONS perties of gallium and itsalloys, and, additionally, some circuit breaker applications thereof.

BACKGROUND OF THE INVENTION The use of gallium and its alloys has beenset forth in the prior art as used as a medium in connection withcircuit breakers. Reference may be made to the following U.S. Pats. Nos.1,948,687; 2,250,212; 2,732,464; 3,331,937; 3,369,094, which teach theuse of gallium broadly as a circuit breaker medium. In addition,reference may be ,.had to the aforesaid patent application by Fox et al.Ser. No. 496,008 for additional uses of gallium in circuit breakerapplications.

However, for high-voltage interruption, it is desirable to establish aplurality of arcs in series so that the voltage per arc may be reduced.In other words, for high-voltage application of circuit breakers, it ishighly desirable to break the arc gap into a number of arc segments,such that the voltage will be distributed equally among the differentgaps. The characteristics of some liquid metals, such as gallium and itsalloys, with very low vapor pressure makes it possible to dothis simplyby the means hereafter described.

SUMMARY OF THE INVENTION It is, accordingly, a general object of thepresent invention to provide an improved high-voltage circuitinterrupter utilizing a liquid metal, such as gallium, for example, andestablishing a plurality of arcs in series.

Still a further object of the present invention is to provide animproved circuit breaker utilizing means for sequentially withdrawingcontacts, or electrodes out of a liquid pool of gallium, or its alloys.

Another object of the present invention is the provision of an improvedgallium-type circuit interrupter utilizing a transverse magnetic fieldfor facilitating lateral movement of the established arcs in the mannerproposed by the instant application.

Still a further object of the present invention is the provision of animproved gallium-type circuit interrupter in which a rotating wheel, ordisc member is utilized to successively rotate a plurality of spacedelectrodes, or contacts out of the liquid pool of gallium, or itsalloys.

According to a preferred embodiment of the invention, a movable contactassembly, comprising a plurality of laterally spaced and insulatedelectrodes having different lengths, is linearly moved upwardly out of apool of liquid gallium, so that the end electrodes first establish apair of arcs. Subsequently, the intervening spaced electrodes arewithdrawn from the same pool of gallium, and the end arcs are preferablylaterally moved from the pool to the adjacent side surfaces of theintervening electrodes. As a result, a plurality of seriallyrelated arcsare established, the number of arcs being equal to the number ofcontacts or electrodes employed.

An additional embodiment of the invention utilizes a rotating insulatingdisc, or wheel carrying along its periphery spokelike radially extendingelectrodes, or contacts, which again are successively withdrawn from theliquid pool of gallium, or its alloys.

Further objects and advantages will readily become apparent upon readingthe following specification taken in con-. junction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front elevational view ofa three-phase circuit breaker embodying the principles of the presentinvention;

FIG. 2 is a side elevational view of the circuit breaker constructionillustrated in FIG. I;

FIG. 3 is a considerably enlarged vertical sectional view taken throughone of the circuit breaker pole-units of the present invention, thecontact structure being shown in the closed-circuit position;

FIGS. 4-7 show, in successive arrangement, the progressive establishmentof the arcs during an opening operation, with FIG. 7 illustrating thefully open circuit position of the circuit breaker unit of the presentinvention;

FIG. 8 is a vertical sectional view taken through a modifiedtype ofcircuit breaker unit employing the principles of the present invention,the contact structure being illustrated in the closed-circuit position;

FIG. 9 is a detailed fragmentary view taken along the line IX-IX of FIG.8 illustrating the rack-and-pinion gear-driving arrangement;

FIG. 10 is a side sectional view taken substantially along the line XXof FIG. 8, the contact structure being shown in the closed circuitposition; and,

FIGS. lI-I4 show successive opening positions of the circuit breakerunit of FIG. 8, with FIG. 14 illustrating the fully open circuitposition of the interrupter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, andmore particularly to FIGS. 1 and 2 thereof, the reference numeral 1designates a circuit breaker of the three-phase type including,generally, an upper interrupting compartment 2 and a lower mechanismcompartment 3. Associated with each pole-unit A, B or C of the circuitbreaker l is a pair of spaced terminal bushings 6, 7 extending throughthe upper cover plate 8 of the unit. The lower ends of the terminalbushings 6, 7 have cable, or strap connections 11, 12 connected to theenclosed vacuum-type circuit breaker unit utilizing gallium 14 in itslower portion. In addition to gallium, various alloys thereof may beused, as set forth in U.S. Pat. application Ser. No. 496,008.

Side-frame supports l6, 17 may be utilized to support the upper andlower compartments 2, 3, as shown in FIGS. 1 and 2. The details of theoperating mechanism are not important to the present invention, itmerely being observed that there is provided a horizontally extendingmain operating shaft 18 having a plurality of crank arms 19, 20 and 21secured thereto, one crank arm being provided for each interrupting unitA, B or C to effect the vertical reciprocal movement of a operating rod,designated by the reference numeral 23, and illustrated more clearly inF IG.3 of the drawings.

As viewed in FIG. I, the left-hand end of the main horizontallyextending operating shaft 18 may have a main crank lever 24 securedthereto, having its free outer end pivotally con nected to a verticallyextending operating rod 25, which extends downwardly into the mechanismcompartment 3, and may be operated by any suitable operating mechanismdisposed therein.

The operating mechanism within the compartment 3 may be of any type,reference being had to U.S. Pat. application filed May 22, I968, Ser.No. 730,983, and assigned to the assignee of the instant invention forone particular type.

With reference to FIG. 3, it will be observed that, generally, there isprovided an evacuated housing 27, composed of a suitable metal havingnonmagnetic properties. Extending downwardly through the upper end ofthe evacuated metal housing 27 is a pair of spaced terminal bushings 29,30, the lower ends of which have cable connections 31, 32 connecting tothe outer ofa plurality of spaced electrodes 33, 34 secured to anmovable with a movable contact assembly, the latter being designated bythe reference numeral 35. The operating rod 23, causing the verticallinear movement of the movable contact assembly 35, is sealed to theupper end of the housing 27 by a metallic bellows 37. The upper end ofthe operating rod 23 is connected to the crank arm 19 of the operatingmechanism (not shown), which has generally the characteristicshereinbefore described in connection with FIGS. 1 and 2.

Disposed in the lower end of the housing 27 is the gallium 14, or itsalloys, which provides a conducting path for the end electrodes 33, 34in the closed circuit position of the device illustrated in FIG. 3. Itwill be observed that there is provided a series blowout coil assembly40 such that the pole-plates 40a thereof provide a transverse magneticfield extending through the evacuated housing 27, the purpose of whichwill become more apparent hereinafter.

During the opening operation, suitable means is provided to efiectupward opening movement of the operating rod 23, which successivelydraws the electrode structure 35 upwardly out of the liquid pool ofgallium metal 14. FIGS. 4--7 show successively the arrangement in whichinitially a pair of end arcs 42, 43 are established, which aretransformed by the transverse magnetic field to the side surfaces 44, 45of the intervening electrodes 44A, 45A. When the intervening electrodes44A, 45A are withdrawn from the liquid pool 14, as shown in FIG. 6, twoadditional arcs 48, 49 are established, there resulting thereby fourarcs 42, 43, 48, 49 in series. The arcs are quickly extinguished becauseof the low-vapor pressure of the gallium, or its alloys.

FIG. 7 shows the fully open circuit position of the circuit breaker unitA in which all of the spaced electrodes 33, 34, 44A, 45A are withdrawnfrom the gallium pool 14.

During the closing operation, suitable means causes a lowering of themovable contact assembly 35 downwardly into the liquid gallium pool 14to a position illustrated in FIG. 3, in which the electrical circuit'isclosed between the line terminal connections L L of each pole unit A, Band C.

It will be observed that in the closed circuit position of theinterrupter l, the metallic housing 27 is at line potential, and

' for this reason it is desirable to support the evacuated housingstructure 27 upon a pair of post-type insulators 52, 53 from thehorizontally extending frame 54, which of course, is at groundpotential.

FIG. 8 illustrates a modification of the invention 56, in which insteadof a linearly movable contact assembly 35, a rotating disc, or wheel 58is utilized. As shown more clearly in FIGS. -44, an insulating wheel 58is rotated by a rack-andpinion arrangement 60, illustrated in FIG. 9,with the operating rod 23 having the same sealed construction 37, asdescribed heretofore. A lateral support 70 may be provided to resistlateral thrust of the gear-driving arrangement.

The cable connections 31, 32 from the lower ends of the terminalbushings 29, 30 are illustrated more clearly in FIG. 10 of the drawings,being attached to the outer electrodes 62, 63. As shown in FIGS. 10--14, the rotation of the wheel 58, as effected by upward movement of theoperating rod 23, and the transmission of rotative movement by therack-and-pinion means 60 causes a successive withdrawing of theelectrodes, or spokelike contacts 62, 63 and 64 out of the liquid poolof gallium 14 to draw the arcs 65, 66, 67, as shown in FIGS. 10 13 ofthe drawings. These arcs are again extinguished by the low vaporpressure of the gallium.

FIG. I4 illustrates the fully open circuit position of the modified-typeof interrupter 56 in which the rotating disc 58 has completely withdrawnall of the spokelike electrodes 62, 63, 64 out of the liquid pool ofgallium 14 to the open circuit position.

The closing operation is provided by a reverse rotation of theinsulating disc 58 to bring the electrodes 62--64 back again into theliquid pool 14 to the position shown in FIG. 10, wherein the linecircuit is again completed through the circuit breaker unit 56 of FIG.8.

From the foregoing description, it will be apparent that there hovelbeen provided novel circuit breaker structures A" and 56 adaptable forhigh-voltage application, in which a number of series arcs areestablished. The advantages of such a system are that the liquid metal14 does not require smooth surfaces for good contact; therefore,erosion, due to arcing. is

not a serious problem. In addition, the liquid metal gallium ing theelectrodes to be made simply and economically. I

Finally, welding of the contacts upon reclosure is eliminated by the useof the liquid metal.

It is to be clearly understood that although there have been illustratedfour electrodes in the embodiment of FIG. 3, and three electrodes in themodification 56 of FIGS. l0-l3, nevertheless, there is no reason why agreater number of intermediate electrodes could not be used, if sodesired.

From the foregoing description, it will be apparent that there has beenprovided a novel means of establishing rapidly a number of series arcsutilizing a suitable liquid metal, such as gallium, or its alloys andadaptable for high-voltageapplications.

Although there has been illustrated and described specific structures,it is to be clearly understood that the same were merely for the purposeof illustration, and that changes and modifications may readily be madetherein by those skilled in the art, without departing from the spiritand scope of the invention..

lclaim:

l. A circuit interrupter comprising, in combination, means defining anevacuated enclosure containing a pool of a conducting liquid metal, amovable contact assembly disposed within said enclosure and having aplurality of spaced electrodes insulatingly supported from each other,line terminal connections for the circuit interrupter, meansconductively connecting the line terminal connections of the interrupterwith the end electrodes of the movable contact assembly, means immersingthe end electrodes of the movable contact assembly into the pool ofliquid metal to close the electrical circuit to the line terminalconnections, and said last-mentioned means being operative to withdrawthe electrodes of the movable contact assembly successively out of thepool of liquid metal to establish a plurality of series arcs.

2. The circuit interrupter combination of claim 1, wherein the liquidmetal comprises gallium or its alloys.

3. The circuit interrupter combination of claim 1, wherein the movablecontact assembly is linearly movable and comprises electrodes ofdifferent length.

4. The combination of claim 3, wherein there are at least fourelectrodes and the end electrodes are shorter in length than the twointervening electrodes.

5. The combination of claim I, wherein the end electrodes of the movablecontact assembly are shorter in length than the intervening electrodes.

6. The combination of claim 1, wherein the movable contact assemblycomprises a rotatable insulating disc carrying the electrodes radiallytherefrom.

7. The combination of claim 1, wherein a transverse magnetic field isprovided to assist in arc movement.

8. The combination of claim 6, wherein a rack-and-pinion drive effectrotating of the insulating disc.

9. The circuit interrupter combination of claim 1, wherein all of theend electrodes are immersed into the pool of liquid metal to close theelectrical circuit in the closed circuit position of the device.

10. The combination according to claim 1, wherein the lastmentionedmeans is operative to withdraw at least one of the end electrodes of themovable contact assembly out of the pool of liquid metal prior to atleast one other electrode to establish a plurality of serially relatedarcs.

11. The circuit interrupter combination of claim 10, wherein the.linnirl mptal rnmnricnc Mm... A. "11......

2. The circuit interrupter combination of claim 1, wherein the liquidmetal comprises gallium or its alloys.
 3. The circuit interruptercombination of claim 1, wherein the movable contact assembly is linearlymovable and comprises electrodes of different length.
 4. The combinationof claim 3, wherein there are at least four electrodes and the endelectrodes are shorter in length than the two intervening electrodes. 5.The combination of claim 1, wherein the end electrodes of the movablecontact assembly are shorter in length than the intervening electrodes.6. The combination of claim 1, wherein the movable contact assemblycomprises a rotatable insulating disc carrying the electrodes radiallytherefrom.
 7. The combination of claim 1, wherein a transverse magneticfield is provided to assist in arc movement.
 8. The combination of claim6, wherein a rack-and-pinion drive effect rotating of the insulatingdisc.
 9. The circuit interrupter combination of claim 1, wherein all ofthe end electrodes are immersed into the pool of liquid metal to closethe electrical circuit in the closed circuit position of the device. 10.The combination according to claim 1, wherein the last-mentioned meansis operative to withdraw at least one of the end electrodes of themovable contact assembly out of the pool of liquid metal prior to atleast one other electrode to establish a plurality of serially relatedarcs.
 11. The circuit interrupter combination of claim 10, wherein theliquid metal comprises gallium or its alloys.